A predominant number of aircraft in the state of the art comprise a single aircraft fuselage on which a wing and a tail unit are arranged. The lift necessary for carrying the weight of the aircraft is, as a rule, generated by the wing, wherein the size of the maximum lift increases by the square of the flight speed and proportionally to the area of the wing. In order to attain an equilibrium of forces and moments in flight it is necessary for the lifting force and the forces generated by the tail unit to form an equilibrium of moments and forces on the center of gravity of the aircraft. Intrinsic stability of an aircraft is achieved when the center of gravity of the aircraft in the direction of flight is in front of the point at which the air forces act, which air forces are caused by the change in the state of equilibrium. Any disturbances in the longitudinal movement then result in the aircraft automatically moving back to a stable position. The equilibrium of moments and forces is achieved in that a horizontal stabilizer unit generates downthrust. As a rule, this downthrust needs to be intensified when for high-lift states the wing increases its lifting force. Thus the total lift of the aircraft is composed of the lift of the wing and of the downthrust of the horizontal stabilizer unit. Furthermore, this means that the downthrust of a horizontal stabilizer unit reduces the overall carrying capacity.
Furthermore, aircraft having a so-called canard configuration are known, in which the horizontal stabilizer units are arranged on a nose of the aircraft fuselage, and the wings are arranged on a tail of the fuselage. In this arrangement the entire lift of the aircraft is determined by the lift both of the wing and of the horizontal stabilizer unit. However, in this arrangement the wing is always in the downwash of the horizontal stabilizer unit, and consequently, due to the associated disturbance, the aerodynamic resistance is increased and the lift per surface area of the rear surface is reduced. For this reason in such configurations the wing area needs to be increased in order to achieve the same carrying capacity.
U.S. Pat. No. 3,884,432 discloses an aircraft having two separate fuselages, a wing arranged between the fuselages, and vertical and horizontal stabilizer units arranged on the fuselages towards the tail.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.